Automatic brake adjuster



March 28, 1939. FlELD 2,152,544-

AUTOMATIC BRAKE ADJUSTER Filed Aug. 5, 1958 Inventor Marcus 6 EI/a/Attorneys Patented Mar. 28, 1939 UNITED STATES AUTOMATIC BRAKE ADJUSTERMarcus H. Field, Canton, Ga., assignor of onethird to R. I. Lathem,Canton, Ga.

Application August 5, 1938, Serial No. 228,298

3 Claims.

This invention relates to automatic brake adjusters and has for theprimary object the provision of a device of this character which willautomatically adjust the brake shoes of a hydraulic brake relative tothe brake drum as wear occurs on the lining of the shoes, so thateilicient operating brakes may be maintained without manual attentionfor the life of the lining and which will not interfere with the normalmovement of the shoes when engaging and disengaging the drum and whichmay be manufactured and sold at a low cost and easily adapted to brakesnow in use.

With these and other objects in view, the invention consists in certainnovel features of construction, combination and arrangement of parts tobe hereinafter more fully described and claimed.

For a complete understanding of my invention, reference is to be had tothe following description and accompanying drawing, in which Figure 1 isa fragmentary vertical sectional view illustrating a brake adjusterconnected with a brake shoe of a hydraulic brake and constructed inaccordance with the present invention.

Figure 2 is a sectional view taken on line 2-2 of Figure 1.

Figure 3 is a sectional view taken on line 33 of Figure 1.

Referring in detail to the drawing, the numeral 5 indicates the usualdust plate or guard associated with a brake drum (not shown) and onwhich is pivotally mounted a brake shoe 6. It is to be understood thatit is customary to have a pair of brake shoes pivotally mounted on thedust plate 5 for coaction with the drum and as each brake shoe will havethe present invention adapted thereto it is not thought necessary toillustrate both brake shoes. The hydraulic means for imparting movementto the brake shoe 6 towards the brake drum is indicated by the characterI and is of a conventional construction. The brake shoe 6 is normallyurged away fr m the brake drum by a coil spring 8. The foregoingdescription briefly sets forth a construction of a hydraulicallyoperated brake shoe to which the present invention is adapted for thepurpose of automatically adjusting the brake shoe relative to the drumas wear occurs on the lining 9 of the brake shoe.

A pin I is secured on the dust plate and is received in a slot ll of anadjusting lever l2 whereby the latter may have a limited slidingmovement as well as a pivotal movement on the dust plate 5. One end ofthe lever I! has pivoted thereto a link 13 which is in turn pivoted onthe brake shoe 8 at a selected distance from the end of the brake shoewhich is in engagement with the hydraulic operating means 1. A leafspring H is secured on the dust plate 5 and overlies the lever l2 toretain the latter on the pivot pin I 0. The other end of the lever I2 isprovided with teeth l5 to engage with ratchet type teeth 16 formed on abar I! mounted on the dust plate and arranged at substantially rightangles to the lever.

In operation, the pivotal connection between the adjusting lever l2 andthe dust plate 5 will permit the brake shoe to have normal pivotalmovement towards and from the brake drum for the purpose of applicationand release of the braking action on the drum. However, when Wear occurson the lining 9 which will permit the brake shoe to increase its pivotalmovement towards the drum in order to bring aboutbraking action, thetoothed end of the adjusting lever advances a tooth on the bar I! sothat the brake 20 shoe on returning to non-drum-engaging position underthe influence of the spring 8 it will be checked in this movement sothat on the application or actuation of the brake shoe again inengagement with the drum the distance of travel 2 of the brake shoetowards the drum will again be normal and consequently bring aboutproper braking action on the drum.

The device shown and described in detail is simple in construction andoperation and may be readily applied to any brake of the hydraulic typenow in use by simply mounting the adjusting lever and the bar II on thedust plate of the brake drum for a limited pivotal and sliding movementand connecting the adjusting lever to the brake shoe by the link I3. Thesimplicity of the construction will permit the device to be manufacturedand sold at a low cost and also will permit the application of thedevice to brakes at a nominal sum and will eliminate the necessity offrequently manually adjusting the brake shoes.

It is believed that the foregoing description when takenin connectionwith the drawing will fully set forth the construction and advantages ofthis invention to those skilled in the art to which such a devicerelates, so that further detailed description will not be required.

What is claimed is:

1. An automatic brake adjuster comprising an adjusting lever, means formounting said lever for pivotal and a limited sliding movement on a dustplate of a brake drum, means for connecting one end of the lever to abrake shoe associated with the drum, and a ratchet mechanism associatedwith the other end of said lever and carried by the dust plate.

2. An automatic brake adjuster comprising an. adjusting lever, means formounting said lever for pivotal and a limited sliding movement on a dustplate of a brake drum, means for connecting the lever to a brake shoeassociated with the drum, teeth formed on the lever, and a rack barhaving ratchet type teeth engageable with the 10 teeth of the lever andmounted on the dust plate.

3. An automatic brake adjuster comprising a pin mounted on a dust plateof a brake drum, a lever having a slot to receive said pin for pivotalmovement and a limited sliding movement, a link pivoted to said leverand to a brake shoe associated with the brake drum, teeth formed on saidlever, a rack bar including ratchet type teeth mounted on the dust plateand engaging the teeth or said lever, and a leaf spring secured on thedust plate and overlying the lever to retain the latter on the pivotpin.

MARCUS H. FIELD.

